Messages in this thread | | | Subject | Re: duration of udelay differs with activated realtime-preempt patch? | From | Steven Rostedt <> | Date | Fri, 25 Nov 2005 08:28:05 -0500 |
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On Fri, 2005-11-25 at 11:26 +0100, Schultheiss, Christoph wrote: > kernel: 2.6.14 with and without the realtime-preempt patch > > hi list, > > after measuring the duration of the function udelay (with oscilloscope > at parallel port), I figured out that udelay (5usec) with activated > realtime- preempt patch lasts a little bit longer. Without the patch the > time is exact. > All kernel debug switches are turned off at compile time. > Can anyone suggest why this happens?
Well, the -rt patch, has changed the udelay function. BTW, you are using the constant udelay, right? Maybe an example of the code you used to test might be useful.
Ingo or John?
-- Steve
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